Radio frequency (RF) switching circuits are used in many different areas of technology for many different purposes. One known use of an RF switching circuit is to switch the range of frequencies that is blocked by the switching circuit from a first range of frequencies to a second range of frequencies, and vice versa. Known RF switching solutions that are used for this purpose include Positive-Intrinsic-Negative (PIN) diodes and gallium arsenide (GaAs) field effect transistors (FETs). Each of these solutions has advantages and disadvantages.
PIN diodes have very good linearity, but consume a relatively large amount of current. In addition, PIN diodes are not easily made using silicon-based integrated circuit (IC) processes. Another drawback is that RF switching circuits that use PIN diodes normally require RF blocking inductors and biasing resistors in order to perform switching with low power loss.
RF switches that use GaAs FETs consume a relatively small amount of current, but have poor linearity unless they are made very large. If they are made very large, they require a large amount of area on the IC. In addition, GaAs FETs generally are not compatible with silicon-based IC processes.
A need exists for an RF switching solution that has good linearity, consumes a relatively small amount of current, is compatible with silicon-based IC processes, and can be implemented in a relatively small area on an IC.